A handwriting-first note app for e-ink tablets. ForestNote is built for low-latency inking on the Viwoods AiPaper Mini and Boox/Onyx devices, so the ink keeps up with your pen instead of lagging a few strokes behind. On any other Android device it falls back to a standard canvas.
Status: version 2.0 release candidate, validated on Viwoods and Boox USI/EMR devices and ready for the final release tag.
- Write with 17 portable brush styles: fountain, five pencil grades, brush, ballpoint, two markers, fineliner, four calligraphy nibs, highlighter, and dashed line.
- Erase by stroke (wipe a whole line) or by pixel (rub out part of one). A hardware eraser button, if your stylus has one, works too.
- Choose a page template — blank, dot, ruled, or grid — per page or as a notebook default, at 5, 7, or 10 mm spacing.
- Organize into notebooks and pages, group notebooks into folders, and browse it all in a Library with thumbnails, search, and a recycle bin.
- Select with the lasso — grab strokes and text together, then cut, copy, delete, drag to move, or paste somewhere else.
- Type text boxes alongside your handwriting, with font, size, weight, and layering.
- Recognize handwriting into editable text on-device (Google ML Kit), no round-trip to a server.
- Transcribe a complete page through an optional OpenAI-compatible or Anthropic-compatible vision endpoint. This is manual-only; local recognition remains available.
- Send a scribble to your calendar — lasso a to-do, and ForestNote turns it into a task on any CalDAV server, queued offline until you're back online.
- Sync across devices against a self-hosted UltraBridge server, with conflict-free multi-master merging.
- Export or back up locally without an account: selected notebooks go to PDF/SVG/ZIP,
and a complete
.forestnote-backupcan be restored through the system file picker.
Step-by-step instructions for each of these live in the user guide.
| Device | How ink is drawn |
|---|---|
| Viwoods AiPaper Mini | Direct ENote digitizer callbacks + firmware partial refresh |
| Boox / Onyx | Onyx Pen SDK — the firmware renders live ink directly to the panel |
| Any other Android (SDK 30+) | Standard canvas redraw — works, but without the firmware speed-up |
The backend is detected at launch. Saved strokes use ForestNote's own brush identities and deterministic renderer; vendor pen styles are only low-latency previews while the stylus is down.
ForestNote ships as a sideloaded APK; there's no Play Store listing. Download the current APK from GitHub Releases, copy it to the tablet, and open it to install.
Install an update over the existing app; do not uninstall first. On first launch, ForestNote offers
an external library under /sdcard/ForestNote or an app-private library. Both work entirely
offline. See Getting started for the storage tradeoff and make a
backup before changing devices or testing sync.
On Viwoods, the fastest ink mode is enabled by default and does not require root. It runs from the same ordinary sideloaded app process as the rest of ForestNote. The setting under Settings → Debug can disable it if a future firmware update breaks the private API; ForestNote then falls back to the older Android-input path. Root was useful to investigate the firmware and to work around the test tablet's restricted package shell, but it is not used by the installed app.
ForestNote is fully usable without network access or an account. Handwriting recognition is optional and downloads a language model on demand (roughly 20 MB per language); recognition runs on the tablet after that. Building from source requires the Viwoods ink and Rhizome repositories as siblings, so follow the complete build guide rather than treating this repository as a standalone Gradle checkout.
Kotlin, Android Views (no Compose), Material 3, minimum SDK 30. Storage is
SQLDelight over SQLite; stroke geometry uses
Jetpack Ink. The build is
multi-module Gradle with shared config in build-logic/.
| Module | Responsibility |
|---|---|
app/notes |
The app — activity, drawing surface, toolbar, Library, settings, recognition, CalDAV, sync wiring |
core/ink |
Ink backends (Viwoods / Boox / generic), the stroke model, coordinate transform, geometry |
core/format |
SQLite storage (folder → notebook → page → stroke) and the sync data binding |
core/sync |
The app-specific sync timing and join policy |
Every stroke is stored in a resolution-independent virtual coordinate space, so notes render the
same across screen sizes and orientations. The documentation index separates
current user/developer references from historical plans and research; module-level CLAUDE.md
files document invariants closest to the code.
Apache 2.0 © 2026 jdkruzr. See LICENSE and NOTICE.